Add metrics for tracking UX impact of non-static CLD data providers

chrome/renderer/translate/translate_helper.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/renderer/translate/translate_helper.h"
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
+#include "base/metrics/histogram.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/renderer/isolated_world_ids.h"
 #include "components/translate/content/common/translate_messages.h"
 #include "components/translate/core/common/translate_constants.h"
 #include "components/translate/core/common/translate_metrics.h"
 #include "components/translate/core/common/translate_util.h"
 #include "components/translate/core/language_detection/language_detection_util.h"
+#include "content/public/common/content_constants.h"
+#include "content/public/renderer/render_thread.h"
 #include "content/public/renderer/render_view.h"
 #include "extensions/common/constants.h"
 #include "extensions/renderer/extension_groups.h"
 #include "ipc/ipc_platform_file.h"
 #include "content/public/common/url_constants.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebElement.h"
 #include "third_party/WebKit/public/web/WebFrame.h"
 #include "third_party/WebKit/public/web/WebNode.h"
 #include "third_party/WebKit/public/web/WebNodeList.h"
@@ skipping 103 matching lines @@
   // header.  The two actually have different meanings (despite the
   // original intent of http-equiv to be an equivalent) with the former
   // being the language of the document and the latter being the
   // language of the intended audience (a distinction really only
   // relevant for things like langauge textbooks).  This distinction
   // shouldn't affect translation.
   WebFrame* main_frame = GetMainFrame();
   if (!main_frame || page_seq_no_ != page_seq_no)
     return;
 
-  // TODO(andrewhayden): UMA insertion point here: Track if data is available.
-  // TODO(andrewhayden): Retry insertion point here, retry till data available.
   if (!cld_data_provider_->IsCldDataAvailable()) {
     // We're in dynamic mode and CLD data isn't loaded. Retry when CLD data
     // is loaded, if ever.
     deferred_page_capture_ = true;
     deferred_page_seq_no_ = page_seq_no;
     deferred_contents_ = contents;
+    RecordLanguageDetectionTiming(DEFERRED);
     return;
   }
 
+  if (deferred_page_seq_no_ == -1) {
+    // CLD data was available before language detection was requested.
+    RecordLanguageDetectionTiming(ON_TIME);
+  } else {
+    // This is a request that was triggered because CLD data is now available
+    // and was previously deferred.
+    RecordLanguageDetectionTiming(RESUMED);
+  }
+
   WebDocument document = main_frame->document();
   std::string content_language = document.contentLanguage().utf8();
   WebElement html_element = document.documentElement();
   std::string html_lang;
   // |html_element| can be null element, e.g. in
   // BrowserTest.WindowOpenClose.
   if (!html_element.isNull())
     html_lang = html_element.getAttribute("lang").utf8();
   std::string cld_language;
   bool is_cld_reliable;
@@ skipping 437 matching lines @@
 }
 
 void TranslateHelper::OnCldDataAvailable() {
   if (deferred_page_capture_) {
     deferred_page_capture_ = false; // Don't do this a second time.
     PageCapturedImpl(deferred_page_seq_no_, deferred_contents_);
     deferred_page_seq_no_ = -1; // Clean up for sanity
     deferred_contents_.clear(); // Clean up for sanity
   }
 }
+
+void TranslateHelper::RecordLanguageDetectionTiming(
+    LanguageDetectionTiming timing) {
+  // The following comment is copied from page_load_histograms.cc, and applies
+  // just as equally here:
+  //
+  // Since there are currently no guarantees that renderer histograms will be
+  // sent to the browser, we initiate a PostTask here to be sure that we send
+  // the histograms we generated.  Without this call, pages that don't have an
+  // on-close-handler might generate data that is lost when the renderer is
+  // shutdown abruptly (perchance because the user closed the tab).
+  DVLOG(1) << "Language detection timing: " << timing;
+  UMA_HISTOGRAM_ENUMERATION("Translate.LanguageDetectionTiming", timing,
+                            LANGUAGE_DETECTION_TIMING_MAX_VALUE);
+
+  // Note on performance: Under normal circumstances, this should get called
+  // once per page load. The code will either manage to do it ON_TIME or will
+  // be DEFERRED until CLD is ready. In the latter case, CLD is in dynamic mode
+  // and may eventually become available, triggering the RESUMED event; after
+  // this, everything should start being ON_TIME. This should never run more
+  // than twice in a page load, under any conditions.
+  // Also note that language detection is triggered off of a delay AFTER the
+  // page load completed event has fired, making this very much off the critical
+  // path.
+  content::RenderThread::Get()->UpdateHistograms(
+      content::kHistogramSynchronizerReservedSequenceNumber);
+}